I've noticed various ways to use the CheckRuleHook.
It seems that one might work better with child objects and the other with parent objects.
Could someone help indicate what the idea behind each of the following syntaxes is and when whould each be used?

' Checks business rules against the specified DataTable
Public Overrides Function CheckRulesHook(ByVal ds As DataSet, ByVal tableName As String) As Boolean
    Dim result As Boolean = True
    Dim RowCount As Integer = ds.Tables(tableName).Rows.Count
    Dim row As Integer

    For row = 0 To RowCount - 1
        Me.DataRow = ds.Tables(tableName).Rows(row)
        Me.CurrentRow = row

        If TypeOf Me.DataRow("Quantity") Is Int16 Then
            Me.ValidateQuantity(CType(Me.DataRow("Quantity"), System.Int16))
            Me.ValidateProductID(CInt(Me.DataRow("ProductID")))
        End If
    Next row

    Return result
End Function

' Checks business rules against the specified DataTable
Public Overrides Function CheckRulesHook(ByVal ds As DataSet, ByVal tableName As String) As Boolean
    Me.ValidateShipName(Me.DataRow("ShipName"))
    Me.ValidateShipRegion(Me.DataRow("ShipRegion").ToString())

    Return Me.ErrorProviderBrokenRuleCount = 0
End Function

    ' Checks business rules against the specified DataTable
    Public Overrides Function CheckRulesHook _
    (ByVal ds As DataSet, ByVal tableName As String) As Boolean
        If Not (ds Is Nothing) Then
            Dim dr As DataRow = ds.Tables(tableName).Rows(0)

            Me.ValidateVisitId(CInt(Me.DataRow("VisitId")))

        End If
        Return Me.ErrorProviderBrokenRuleCount = 0
    End Function

Perhaps a brief walkthough of what each of these examples is attempting to do would be useful.